KR20160027137A - Polyethylene composition for pipe and pipe coating applications - Google Patents

Abstract

The present invention relates to an ethylene copolymer comprising at least one alpha olefin comonomer having from 3 to 12 carbon atoms and having a density measured according to ISO 1183-1: 2004 of not less than 940.0 kg / m < 3 > and not more than 952.5 kg / m & A composition comprising said polyethylene composition, and a use of said polyethylene composition for the manufacture of a product, said composition having a melt flow rate MFR ₅ (190 캜, 5 kg), measured according to ISO 1133, of from 0.10 to 3.0 and g / 10min, the shear storage modulus G '(2 kPa) and the 600Pa to 900Pa, the shear thinning index SHI _{2 .7 / 210} and 20 to 50, the composition molar content of comonomer in the base resin in accordance with the following formula: a polyethylene composition having a breaking elongation (EB) at -45 DEG C that is dependent on (mol. CC)
EB [%] ≥ 175 [% / mol%] · mol. CC [mol%]
Wherein said elongation at break is measured according to ISO 527-1 at a temperature of -45 DEG C and the molar content (mol. CC) of said comonomer is greater than the molar content of said alpha-olefin units in the total content of monolithic units of said base resin. Is the molar content of the olefin comonomer.

Description

[0001] POLYETHYLENE COMPOSITION FOR PIPE AND PIPE COATING APPLICATIONS [0002]

The present invention is directed to polyethylene, especially polyethylene for pipe and pipe coating applications. The present invention also relates to a process for producing polyethylene.

A number of polyethylene compositions for use in pipe making are known. The pipe material is classified as PE80 or PE100. The operating temperature of PE100 is 20 ℃. The ISO 9080 standard ensures that PE100 materials have a life of at least 50 years at 20 ° C when using an internal stress of 10 MPa.

Japanese Patent Laid-Open Publication No. 11-058607 A2 discloses that a steel pipe coated with a polyolefin exhibits excellent low-temperature impact resistance characteristics at -60 ° C. In order to obtain such characteristics, it is proposed that the above-mentioned Japanese Patent Laid-open Publication No. 2000-22995 uses a polyethylene resin having a density of 0.915 to 0.935 g / cm3.

European patent EP 0679704 A1 also deals with improving impact resistance at low temperatures, such as temperatures of -45 占 폚 or below. In order to achieve this object, the above-mentioned European patent discloses the use of a high-pressure, low-density polyethylene having a density of 0.915 to 0.930 g / cm 3 and a blend of an ethylene-olefin copolymer having a density of 0.895 to 0.920 g / cm 3 .

On both sides of Japanese Laid-Open Patent JP-11-106682 A2 and Japanese Laid-Open Patent JP-09-143400 A2, there is proposed a process for producing a polyurethane foam comprising an ethylene polymer modified with an acid, a polyethylene having various densities, and a blend of ethylene polymers comprising an elastomeric component A resin composition suitable for powder coating is disclosed.

European patent EP 1555292 A1 discloses polymer compositions suitable for extrusion coating, for example to prepare multilayer materials, which comprise various high density polyethylene and low density polyethylene.

European patent EP2072587A1 deals with coated pipes with various polyethylene layers. The various ethylene copolymers have 4 to 10 carbon atoms, a weight average molecular weight of 70000 g / mol to 25000 g / mol, a melt index MFR ₂ 0.05g / 10min to about 5g / 10min, a melt index MFR ₅ 0.5 to 10g / 10min, density 945kg / ㎥ to 958kg / ㎥ of one or more alpha-olefin comonomers, and copolymers of ethylene. The coatings described above have high strength, excellent properties at elevated temperatures, and suitable stress-cracking properties.

Tanks, drainage systems, soil and waste pipe systems, etc., are used at very low temperatures. Polyethylene pipes and pipe coatings tend to be brittle at low temperatures below 0 ° C, such as -45 ° C.

In particular, the application of steel pipe coatings to low temperature fuels such as Russia is an important parameter for transport, storage and installation of coated steel pipes at low temperatures of -45 ° C. On the other hand, in order to improve other parameters such as abrasion resistance, stiffness, and crystallization rate, the elongation at break is decreased according to the increased polymer density. The density of the polyethylene resin can be directly affected by its comonomer content.

WO 2007/141022 discloses a polyethylene composition for steel pipe top coating which exhibits excellent elongation at break at -45 캜. However, the base resin of these compositions has a fairly low density, not higher than 940 kg / m3.

Polyethylene compositions for pipe coatings such as pipes and especially steel pipe top coatings are still low comonomer content and therefore require high low temperature fracture elongation in high density mastic resins.

The present invention relates to a polyethylene pipe and an upper coating, wherein when the polyethylene pipe and top coating are made from the following polyethylene composition, the polyethylene pipe and the top coating have improved fracture elongation at -45 캜 and improved Charpy notched impact strength at 0 캜. Temperature property balance: wherein the polyethylene composition is an ethylene copolymer having at least one alpha olefin comonomer having from 3 to 12 carbon atoms and is measured according to ISO 1183-1: 2004 Lt; 3 > and 952.5 kg / m < 3 > or less,

The compositions are particularly the melt flow rate measured according to ISO 1133 (190 ℃, 5kg) is 0.10 to 3.0g / 10min, the storage modulus G '(2kPa) The 600Pa to 900Pa, shear thinning index (shear thinning index) SHI _{2. 7/210} is 20 to 50,

The composition has an elongation at break (EB) at -45 캜, depending on the molar content (mol. CC) of the comonomer of the base resin according to the following formula:

EB [%] ≥ 175 [% / mol%] · mol. CC [mol%]

Wherein said elongation at break is measured according to ISO 527-1 at a temperature of -45 DEG C and the molar content (mol. CC) of said comonomer is greater than the molar content of said alpha-olefin units in the total content of monolithic units of said base resin. Lt; RTI ID = 0.0 > olefin < / RTI > comonomer.

The polyethylene composition of the present invention surprisingly exhibits improved low temperature properties as well as excellent mechanical properties at high temperatures such as 23 deg.

Thus, the present invention is an ethylene copolymer having at least one alpha olefin comonomer having from 3 to 12 carbon atoms and having a density of greater than 940.0 kg / m < 3 > and not greater than 952.5 kg / m & ≪ / RTI >

Wherein the composition has a melt flow rate (190 占 폚, 5 kg) of 0.10 to 3.0 g / 10 min measured according to ISO 1133, a storage modulus G '(2 kPa) of 600 Pa to 900 Pa, a shear thinning index SHI ₂ is _{0.7 / 210} of from 20 to 50,

The composition has a breaking elongation (EB) at -45 캜 which is dependent on the molar content (mol. CC) of the comonomer of the base resin according to the following formula:

EB [%] ≥ 175 [% / mol%] · mol. CC [mol%]

Wherein said elongation at break is measured according to ISO 527-1 at a temperature of -45 DEG C and the molar content (mol. CC) of said comonomer is greater than the molar content of said alpha-olefin units in the total content of monolithic units of said base resin. Lt; RTI ID = 0.0 > olefin < / RTI > comonomer.

1. A polyethylene composition produced by a multistage process, the multistage process comprising:

a) polymerizing ethylene under a catalyst in the first reactor as an intermediate step of preparing a melt flow rate MFR ₂ (190 °, 2.16kg) is from 100 to 400 g / 10min,

Wherein the catalyst is a silica supported Ziegler-Natta catalyst having a molar composition comprising:

Al: 1.30 to 1.65 mol / kg silica, preferably 1.33 to 1.63 mol / kg silica, more preferably 1.35 to 1.60 mol / kg silica,

Mg: 1.25 to 1.61 mol / kg silica, preferably 1.26 to 1.60 mol / kg silica, more preferably 1.30 to 1.55 mol / kg silica,

Ti: 0.70 to 0.90 mol / kg silica, preferably 0.71 to 0.88 mol / kg silica, more preferably 0.72 to 0.8 mol / kg silica,

The average particle size (D50) is 7 to 15 mu m, preferably 8 to 12 mu m;

b) transferring the reaction product to a gas phase reactor,

(i) supplying ethylene and a comonomer to the gas phase reactor,

(ii) further polymerizing the intermediate,

Producing a base resin having a density of not less than 940.0 kg / m 3 and not more than 952.5 kg / m 3, measured according to ISO 1183-1: 2004; And

c) extruding the base resin into a polyethylene composition,

The polyethylene composition has a melt flow rate MFR ₅ (190 캜, 5 kg) of 0.10 to 3.0 g / 10 min, a storage modulus G '(2 kPa) of 600 Pa to 900 Pa, a shear thinning index SHI _{2.7 / 210} Is 20 to 50 and has a breaking elongation (EB) at -45 캜 which is dependent on the molar content (mol. CC) of the comonomer of the base resin according to the formula:

EB [%] ≥ 175 [% / mol%] · mol. CC [mol%]

Here, the elongation at break (EB) is measured according to ISO 527-1 at a temperature of -45 DEG C, and the molar content (mol. CC) of the comonomer is determined by the alpha Lt; RTI ID = 0.0 > olefin < / RTI > comonomer.

In another aspect, the invention provides an article comprising an ethylene composition according to the present invention.

In another aspect, the invention relates to the use of the polyethylene composition of the present invention for making articles.

Thus, in one embodiment of the present invention, the article is associated with a pipe or pipe fitting.

In another embodiment of the present invention, the article relates to a pipe wherein the outer surface of the pipe is coated with a coating layer comprising a polyethylene composition according to the invention.

The catalyst used in the present invention is preferably prepared by the following method:

(i) a compound of the formula Mg (R) ₂ (Wherein each R is the same or different alkyl group having 1 to 10 C-atoms, preferably 2 to 10 C-atoms) is most preferably butyloctylmagnesium. The alcohol of formula R'OH, wherein R 'is an alkyl group having 2 to 16 C-atoms, preferably 4 to 10 C-atoms, is most preferably 2-ethyl-hexanol. In an aromatic solvent at a molar ratio of 1: 1.70 to 1: 1.95, preferably 1: 1.75 to 1: 1.90, to prepare a magnesium complex,

(ii) filling the reactor with an aliphatic hydrocarbon solvent having an average particle size (D50) of 7 to 15 占 퐉, preferably 8 to 12 占 퐉 and a calcined silica, preferably pentane,

(iii) a compound of the formula AIR _n X _{3 -n} , wherein R is a C ₁ to C ₁₀ alkyl group, preferably a C ₂ to C ₆ alkyl group, most preferably a C ₂ to C ₄ alkyl group, and X is Halogen, preferably a chloride, and n is 1 or 2, preferably 1,

At a temperature of 10 to 70 DEG C, preferably 20 to 60 DEG C, and most preferably 40 to 50 DEG C (the aluminum compound is preferably ethylaluminum dichloride)

(iv) contacting the magnesium complex prepared in step i) with 2.40 to 2.70 mol Mg / kg silica, preferably from 2.45 to 2.65 mol%, at 20 to 50 DEG C, preferably 30 to 50 DEG C, most preferably 40 to 50 DEG C. mol Mg / kg silica,

(v) adding a further aliphatic hydrocarbon solvent, preferably pentane, into the reactor and maintaining a temperature of at least 40 < 0 > C,

(vi) stirring the mixture at a temperature of 45 to 55 DEG C for 3 to 5 hours,

(vii) adding an amount of 1.40 to 1.65mol / kg by silica TiCl ₄ to the reactor for at least 1 hour at a temperature of 45 to 55 ℃,

(viii) mixing said catalyst mixture at 50 to 60 DEG C for at least 5 hours, and

(ix) drying the catalyst mixture in a vacuum and / or nitrogen stream.

The addition of Al, Mg and Ti compounds is preferably carried out within 1 to 3 hours, more preferably after each addition step, the mixture is further stirred for 1 to 6 hours.

Justice

The polyethylene composition according to the invention means a polymer derived from at least 50 mol% of ethylene monomer units and additional comonomer units.

Thus, the ethylene homopolymer is meant to consist essentially of ethylene monomer units. Depending on the requirements of the large scale polymerization reaction, the ethylene homopolymer may contain small amounts of comonomer units, which are usually not more than 0.1 mol%, preferably not more than 0.05 mol%, based on the ethylene homopolymer, Or less, most preferably 0.01 mol% or less.

The term " base resin " refers to a polymer portion of a composition that is free of fillers such as carbon black. Those skilled in the art will appreciate that the measurement of the base resin requires the presence of a stabilizer.

In addition to the basic resin, common additives such as pigments (e.g., carbon black), stabilizers (e.g., antioxidants), antacids and / or anti-UV agents, antistatic agents and utilization agents May be present in the polyethylene composition. The content of these additives is preferably 10 wt% or less, more preferably 8 wt% or less, and most preferably 5 wt% or less, based on the composition.

The composition contains a content of carbon black of preferably 8 wt% or less, more preferably 1 to 4 wt% or less, based on the total content of the composition.

The content of the additive other than carbon black is preferably 1 wt% or less, more preferably 0.5 wt% or less.

The polydispersity index (PI) is a rheological measure of the broadness in a molecular weight distribution curve.

The term "catalyst system" may be a catalyst and a composition prepared with a cocatalyst.

Normal

Base resin

The base resin according to the present invention is an ethylene copolymer having at least one alpha olefin comonomer having 3 to 12 carbon atoms. Preferably, the alpha olefin comonomer is selected from alpha olefins having from 4 to 8 carbon atoms such as 1-butene, 1-hexene, 4-methyl-1-pentene, and 1-octene. Particularly preferred are 1-butene and 1-hexene.

The ethylene copolymer may further comprise comonomers, polar comonomers or silicon containing comonomers other than alpha olefins such as diene. However, it is preferred that the ethylene copolymer contains only alpha olefins as comonomer units.

It is particularly preferred that the ethylene copolymer comprises 1-butene or 1-hexene as comonomer units.

The content of the units derived from at least one of the alpha olefin comonomers having 3 to 12 carbon atoms is preferably 0.1 to 3.0 mol%, more preferably 0.2 to 2.0 mol%, most preferably 0.3 to 2.0 mol% 1.5 mol%.

In one embodiment particularly suitable for pipe and pipe fitting applications, the content of units derived from one or more alpha olefin comonomers having from 3 to 12 carbon atoms in the base resin is preferably the lower limit of the aforementioned range. In this embodiment, the content of the units derived from one or more alpha olefin comonomers having 3 to 12 carbon atoms in the base resin is preferably 0.1 to 2.0 mol%, more preferably 0.2 to 1.5 mol% , Preferably 0.3 to 1.2 mol%, and most preferably 0.4 to 0.8 mol%.

In another embodiment particularly suitable for pipe coating applications, the content of units derived from one or more alpha olefin comonomers having from 3 to 12 carbon atoms in the base resin is preferably an upper limit of the above-mentioned range. In this embodiment, the content of the units derived from at least one alpha-olefin comonomer having 3 to 12 carbon atoms in the base resin is preferably 0.25 to 3.0 mol%, more preferably 0.5 to 2.0 mol% , Preferably 0.75 to 1.5 mol%, and most preferably 1.0 to 1.25 mol%.

Density (base resin)

The base resin according to the present invention has a density of 940.0 kg / m 3 or more and 952.5 kg / m 3 or less. Preferably, the density of the base resin is 941.0 kg / m3 or more and 952.0 kg / m3 or less, more preferably 942.0 kg / m3 or more and 951.0 kg / m3 or less.

In one embodiment particularly suitable for pipe and pipe fitting applications, the density of the base resin is preferably the upper limit of the above-mentioned range for the base resin. In this embodiment, the density of the base resin is preferably 947.0 kg / m3 or more and 952.5 kg / m3 or less, more preferably 948.0 kg / m3 or more and 951.5 kg / m3 or less, and most preferably 949.0 kg / m3 And 951.0 kg / m < 3 > or less.

In another embodiment particularly suitable for pipe coating applications, the density of the base resin is preferably the lower limit of the above-mentioned range for the base resin. In this embodiment, the density of the base resin is preferably more than 937.0 kg / m 3 and not more than 948.0 kg / m 3, more preferably not less than 938.0 kg / m 3 and not more than 944.0 kg / m 3, And 942.0 kg / m < 3 > or less.

Elongation at break (-45 ° C)

The composition according to the invention has a breaking elongation (EB) at -45 캜 which is dependent on the molar content (mol. CC) of the comonomer of the base resin according to the following formula:

EB [%] ≥ 175 [% / mol%] · mol. CC [mol%]

Preferably, the elongation at break (EB) of the composition at -45 캜 is dependent on the molar content (mol. CC) of the comonomer of the base resin according to the following formula:

EB [%] ≥ 200 [% / mol%] · mol. CC [mol%]

More preferably, the following formula is satisfied.

EB [%] ≥ 250 [% / mol%] · mol. CC [mol%]

Most preferably, the following formula is satisfied.

EB [%] ≥ 300 [% / mol%] · mol. CC [mol%]

The breaking elongation (EB) is measured according to ISO 527-1 at a temperature of -45 DEG C, and the molar content (mol. CC) of the comonomer is determined by the alpha-olefin bond It reflects the molar content of the monomer.

The base resin includes ethylene homopolymers or ethylene copolymers in which at least two fractions (A) and (B) have different weight average molecular weights (Mw).

Wherein said fraction (A) is an ethylene homopolymer and said fraction (B) is a copolymer of ethylene and at least one alpha-olefin comonomer unit having from 3 to 12 carbon atoms,

Here, the fraction (A) has a melt flow rate MFR ₂ (190 °, 2.16 kg) of 100 to 400 g / 10 min, and the fraction (A) is present in an amount of 44 to 54 wt% with respect to the base resin.

The ethylene homopolymer fraction (A) preferably has a melt flow rate MFR ₂ (190 °, 2.16 kg) of 150 to 350 g / 10 min, more preferably 200 to 300 g / 10 min.

The density of fraction (A) is preferably at least 970 kg / m3.

Further, the fraction (A) is preferably 45 to 53 wt%, more preferably 46 to 52 wt%, based on the base resin in the presence of the base resin.

Fraction (B) is a copolymer of ethylene and at least one alpha olefin comonomer having from 3 to 12 carbon atoms. The alpha olefin comonomer is preferably selected from alpha olefins having from 4 to 8 carbon atoms, such as 1-butene, 1-hexene, 4-methyl-1-pentene and 1-octene. Particularly preferred are 1-butene and 1-hexene.

Fraction (B) may further comprise comonomers, polar comonomers or silicon containing comonomers other than alpha olefins such as dienes. On the other hand, it is preferred that the fraction (B) contains only alpha-olefin monomers as comonomer units.

Particularly preferred are 1-butene and 1-hexene.

The content of units derived from at least one alpha olefin comonomer having 3 to 12 carbon atoms in fraction (B) is preferably 0.4 to 5.5 mol%, more preferably 0.5 to 5.0 mol%, most preferably 0.6 To 4.5 mol%.

Optionally, the base resin may further comprise a prepolymer fraction. The prepolymer fraction is preferably an ethylene homopolymer. The prepolymer fraction is preferably present in an amount of 0 to 5 wt%, more preferably in an amount of 0.2 to 2.5 wt%, most preferably in an amount of 0.5 to 1.5 wt%.

In one embodiment of the present invention, the base resin is composed of only the above-mentioned fractions (A) and (B).

In another embodiment of the present invention, the base resin is composed of fractions (A) and (B) and a prepolymer fraction as described above.

The latter embodiment is preferred over the former embodiment.

Polyethylene composition

The polyethylene composition may be further characterized according to the following characteristics:

Rheological properity

The polyethylene composition may be further characterized by the following special properties.

PI

Wherein the polyethylene composition has a polydispersity index (PI), preferably in, more preferably in the range of ^-1 than 3.0Pa and 1.5Pa ^-1 or less in the range of ^-1 than 2.5Pa and 1.7Pa ^-1 or less.

SHI _{2 .7 / 210}

Wherein the polyethylene composition has a shear thinning index SHI _{2 .7 / 210} of from 20 to have a 50, more preferably the shear thinning index SHI _{2 .7 / 210} of 21 to 45, and most preferably the shear thinning index SHI _{2.7 / 210} Lt; / RTI >

The shear thinning index SHI _{2 .7 / 210} is the relative amount of low molecular weight and high molecular weight material is changed (through the division of the reactor), for example the low by changing the input of the chain transfer agent (chain transfer agent) Can be modified for the catalyst systems provided by varying the molecular weight of each of the molecular weight and high molecular weight materials. Moreover, other catalyst systems result in a specific inherent shear discrepancy index.

SHI _1/100

The polyethylene composition is an extrapolation (extrapolated) the shear thinning index SHI _1/100, preferably from 5 to 20, more preferably from 7 to 18, most preferably from 10 to 16.

The shear thinning index SHI _1/100 is the The SHI _{2 .7 / 210} shear discontinuity index can be modified as described above. Furthermore, the shear thinning index SHI _1/100 is particularly accurate in uniquely provided by the molecular weight distribution of the catalyst system.

G '(5 kPa)

The polyethylene composition according to the present invention has a storage elastic modulus G '(5 kPa), preferably 2000 Pa to 2700 Pa, more preferably 2100 Pa to 2550 Pa, and most preferably 2150 Pa to 2500 Pa.

G '(2 kPa)

The polyethylene composition according to the present invention has a storage elastic modulus G '(2 kPa), preferably 600 Pa to 900 Pa, more preferably 650 Pa to 880 Pa, even more preferably 700 Pa to 860 Pa, and most preferably 720 Pa to 845 Pa.

The storage modulus is largely influenced by the content of very high molecular weight substances. A low value storage elastic modulus G '(2 kPa) shows a qualitatively narrow molecular weight distribution diagram from a normal point of view.

Complex viscosity eta0.05 rad / s

The polyethylene composition according to the present invention has a complex viscosity at 0.05 rad / s eta *, preferably 100000 Pa-s to 220,000 Pa-s, more preferably 115000 Pa-s to 200000 Pa-s, still more preferably 120000 Pa-s And most preferably from 130,000 Pa · s to 170,000 Pa · s.

Complex viscosity eta300rad / s

The polyethylene composition according to the invention preferably has a complex viscosity at 300 rad / s eta *, preferably from 1050 Pa · s to 1750 Pa · s, more preferably from 1200 Pa · s to 1600 Pa · s and most preferably from 1250 Pa · s to 1500 Pa · S.

Viscosity at constant shear stress of 747 Pa eta747

The polyethylene composition according to the present invention preferably has a viscosity at a constant shear stress of 747 Pa, preferably from 150000 Pa · s to 75000 Pa · s, more preferably from 220000 Pa · s to 600000 Pa · s, most preferably from 270000 Pa · s to 550000 Pa · s s.

The viscosity at a constant shear stress of 747 Pa is affected by the mass average molecular weight and is a measure of the sagging property of the polyethylene composition.

As described _{above, PI, SHI 2 .7 / 210} , SHI 1/100, G '(5kPa), G' (2kPa), eta0.05rad / s, the rheological properties, such as eta300rad / s and eta747 is carbon black Lt; RTI ID = 0.0 > of the < / RTI > base resin. On the other hand, such properties can also be measured for the base resin. The measured rheological properties for the base resin are preferably in the same range as measured for the polyethylene composition.

MFR ₅

The composition according to the present invention has a melt flow rate MFR ₅ (190 캜, 5 kg) of 0.10 to 3.0 g / 10 min, preferably 0.15 to 2.7 g / 10 min, more preferably 0.20 to 2.5 g / 10 min. The MFR ₅ (190 캜, 5 kg) is measured according to ISO 1133.

In one embodiment particularly suitable for pipe and pipe fitting applications, MFR ₅ (190 캜, 5 kg) of the composition is preferably the lower limit of the above-mentioned range. In this embodiment, the MFR ₅ (190 캜, 5 kg) of the composition is preferably in the range of 0.10 to 0.40 g / 10 min, more preferably in the range of 0.15 to 0.35 g / 10 min, and most preferably in the range of 0.20 to 0.30 g / 10 min.

In another embodiment particularly suitable for pipe coating applications, MFR ₅ (190 캜, 5 kg) of the composition is preferably an upper limit of the above-mentioned range. The MFR ₅ (190 캜, 5 kg) of the composition in this embodiment is preferably in the range of 1.0 to 4.0 g / 10 min, more preferably in the range of 1.5 to 3.5 g / 10 min, and most preferably 1.8 to 3.0 g / 10 min.

MFR ₂₁

In one embodiment particularly suitable for pipe and pipe fitting applications, the melt flow rate MFR ₂₁ (190 占 폚, 21.6 kg) of the composition according to the invention is preferably 1.5 to 13.5 g / 10 min, more preferably 2.5 To 11.0 g / 10 min, and most preferably from 5.0 to 7.5 g / 10 min. The MFR ₂₁ (190 캜, 21.6 kg) is measured according to ISO 1133.

In another embodiment particularly suitable for pipe coating applications, the melt flow rate MFR ₂₁ (190 占 폚, 21.6 kg) of the composition according to the invention is preferably 10 to 60 g / 10 min, more preferably 20 to 50 g / 10 min, and most preferably 30 to 45 g / 10 min. The MFR ₂₁ (190 캜, 21.6 kg) is measured according to ISO 1133.

MFR ₂

In another embodiment particularly suitable for pipe coating applications, the melt flow rate MFR ₂ (190 占 폚, 2.16 kg) of the composition according to the invention is preferably 0.20 to 1.5 g / 10 min, more preferably 0.35 to 1.3 g / 10 min, and most preferably 0.4 to 1.2 g / 10 min. The MFR ₂ (190 캜, 2.16 kg) is measured according to ISO 1133.

Particularly suitable for pipe and pipe fitting applications, the MFR ₂ of the composition is generally not precisely specified, but less than 0.1 g / 10 min is suitable.

FRR _21/5

The polyethylene composition according to the present invention has MFR ₂₁ The ratio of the flow rate ratio of _{MFR 5 (flow rate ratio) FRR} 21/5 a, preferably 15 to 40, more preferably from 17 to 35, even more preferably 19 to 30, most preferably from 21 to 28.

Density (composition)

The composition according to the invention has a density of greater than 945.0 kg / m 3 and less than 966.0 kg / m 3, preferably greater than 947.0 kg / m 3 and less than 965.5 kg / m 3, as measured according to ISO 1183-1: Is higher than 948.5 kg / m 3 and not higher than 965.0 kg / m 3.

The density of the composition is affected by the density of the base resin and can be further adjusted by the content of the filler such as carbon black in the composition.

The density of the base resin is mainly affected by the content and type of the comonomer.

In view of the description of the density of the base resin, the density of the composition in the first embodiment, which is particularly suitable for pipe and pipe fittings, is preferably an upper limit of the stated range. The density of the composition of this embodiment is preferably at least 956.0 kg / m 3 and at most 966.0 kg / m 3, more preferably at least 957.0 kg / m 3 and at most 965.5 kg / m 3, most preferably at least 958.5 kg / Lt; 3 > / kg or less.

In another embodiment particularly suitable for pipe coating applications, the density of the composition is preferably the lower limit of the stated range. In this embodiment, the density of the composition is preferably at least 945.0 kg / m 3 and at most 966.0 kg / m 3, more preferably at least 947.0 kg / m 3 and at most 963.5 kg / m 3, And 962.0 kg / m < 3 > or less.

In addition, the properties of the polymer mainly derived from the melt flow rate as well as the catalyst used play a part. It is also emphasized that the comonomer need not be a single comonomer. In addition, the mixture of comonomers may be as described above.

Molecular weight distribution

The composition according to the invention has a Mw / Mn molecular weight distribution which is the ratio of the weight average molecular weight to the number average molecular weight and is in the range of 10 to 30, preferably 13 to 27, more preferably 15 to 25, 22.

Charpy Notch Impact Strength (0 C)

The composition according to the present invention has a Charpy Notch impact strength of not less than 10 kJ / m 3, preferably not less than 15 kJ / m 3, more preferably not less than 18 kJ / m 3, most preferably not less than 20 kJ / m 3, measured according to ISO 179eA at 0 ° C to be. The upper limit of the Charpy Notch impact strength generally does not exceed 50 kJ / m 3.

Tensile modulus (23 ° C)

The composition according to the invention has a tensile modulus of at least 900 MPa, preferably at least 950 MPa, more preferably at least 1000 MPa, most preferably at least 1030 MPa, measured according to ISO 527-2: 1993 at 23 ° C. The upper limit of the tensile modulus at 23 캜 is generally not higher than 1800 MPa, preferably not higher than 1500 MPa.

Tensile Properties (-45 ℃)

The composition according to the invention preferably has a breaking elongation measured according to ISO 527-1: 1993 at -45 캜 and is at least 75%, more preferably at least 100%, even more preferably at least 147% 200% or more. The upper limit of the elongation at break at -45 캜 is generally not more than 500%, more preferably not more than 400%.

The composition according to the present invention has a tensile strength, measured according to ISO 527-1: 1993 at -45 캜, of at least 35 MPa, more preferably at least 40 MPa, most preferably at least 45 MPa. The upper limit of the tensile strength at -45 캜 is generally not more than 100 MPa, more preferably not more than 75 MPa.

The composition according to the invention has a tensile stress at the yield point calculated according to ISO 527-1: 1993 at -45 캜, which is at least 35 MPa, more preferably at least 40 MPa, most preferably at least 45 MPa. The upper limit of the tensile stress at -45 캜 is generally not more than 100 MPa, more preferably not more than 75 MPa.

Has a tensile strain at the yield point measured according to ISO 527-1: 1993 at -45 캜 according to the composition of the present invention, which is at least 4.0%, more preferably at least 4.5%, even more preferably at least 5.0% It is preferably at least 5.5%. The upper limit of the tensile strain calculated at -45 캜 generally does not exceed 10.0%, more preferably does not exceed 8.0%.

In another aspect, the present invention is a polyethylene composition produced by a multistage process, the multistage process comprising:

a) polymerizing ethylene under a catalyst in the first reactor as an intermediate step of preparing a melt flow rate MFR ₂ (190 °, 2.16kg) is from 100 to 400 g / 10min,

Wherein the catalyst is a silica supported Ziegler-Natta catalyst having a molar composition comprising:

Al: 1.30 to 1.65 mol / kg silica, preferably 1.33 to 1.63 mol / kg silica, more preferably 1.35 to 1.60 mol / kg silica

Mg: 1.25 to 1.61 mol / kg silica, preferably 1.26 to 1.60 mol / kg silica, more preferably 1.30 to 1.55 mol / kg silica

Ti: 0.70 to 0.90 mol / kg silica, preferably 0.71 to 0.88 mol / kg silica, more preferably 0.72 to 0.85 mol / kg silica,

Having a mean particle size (D50) of 7 to 15 占 퐉, preferably 8 to 12 占 퐉;

b) transferring the reaction product to a gas phase reactor,

(i) supplying ethylene and a comonomer to the gas phase reactor,

(ii) further polymerizing the intermediate,

Producing a base resin having a density of not less than 940.0 kg / m 3 and not more than 952.5 kg / m 3, measured according to ISO 1183-1: 2004; And

c) extruding the base resin into a polyethylene composition,

Wherein the polyethylene composition has a melt flow rate measured according to _{ISO 1133 MFR 5 (190 ℃,} 5kg) is 0.10 to 3.0g / 10min, and the storage elastic modulus G '(2kPa) The 600Pa to 900Pa, the shear thinning index SHI _{2 .7 / 210} is from 20 to 50 and has a breaking elongation (EB) at -45 캜 dependent on the molar content (mol. CC) of the comonomer of the base resin according to the following formula:

EB [%] ≥ 175 [% / mol%] · mol. CC [mol%]

Wherein said elongation at break is measured according to ISO 527-1 at a temperature of -45 DEG C and the molar content (mol. CC) of said comonomer is greater than the molar content of said alpha-olefin units in the total content of monolithic units of said base resin. Lt; RTI ID = 0.0 > olefin < / RTI > comonomer.

The intermediate preferably comprises, and more preferably consists of, fraction (A) as described above and optionally a prepolymer fraction.

The base resin and the polyethylene composition produced by the above-described multi-step process are preferably additionally defined by the characteristics of the base resin and the polyethylene composition described above.

article

In another aspect, the invention is directed to an article comprising the polyethylene composition described above.

Thus, in an embodiment of the invention, the article relates to a pipe or pipe fitting.

In another aspect of the present invention, the article is coated with a pipe, and the outer surface of the pipe is coated with a coating layer comprising the polyethylene composition according to the present invention. The coating on the outer surface of the pipe preferably comprises three coating layers, wherein the innermost coating layer is a corrosion inhibiting layer, the intermediate layer is an adhesive layer, and the outer coating layer is a polyethylene layer (top coating layer). Thus, the top coating layer preferably comprises the polyethylene composition according to the invention.

Manufacturing method

The novel polyethylene composition is prepared by polymerizing each copolymerized ethylene in a multi-stage reactor cascade formed by at least one of a first reactor and a second reactor. Here, the first reactor is preferably a loop reactor, and more preferably, the second reactor is a gas phase reactor.

The polymerization reaction is carried out with silica carrying a catalyst having a molar composition of Al 1.30 to 1.65 mol / kg silica, Mg 1.25 to 1.61 mol / kg silica, and Ti 0.70 to 0.90 mol / kg silica.

The average particle size of the catalysts used in the art is generally from 10 to 100 mu m. On the other hand, according to the present invention, it has been found that a special advantage can be obtained when the catalyst has a mean particle size (D50) of 7 to 15 mu m, preferably 8 to 12 mu m.

The particle size of the catalyst is mainly affected by the particle size of the carrier, in this case silica carrier. Thus, a carrier suitable for the catalyst used in the present invention may have a reasonably small particle size, for example, silica having an average particle size (D50) of less than 15 microns, preferably from 7 to 15 microns, . An example of a suitable silica support is Sylopol 2100, available from Grace.

The magnesium compound is the reaction product of magnesium dialkyl and alcohol. The alcohol is a linear or branched aliphatic monoalcohol. The alcohol preferably has 6 to 16 carbon atoms. Particularly preferred are branched alcohols, and 2-ethyl-1-hexanol is the most preferred alcohol.

The magnesium dialkyl may be one of the magnesium compounds bonded to the same or different two alkyl groups. Butyl-octyl magnesium is a preferred example of magnesium dialkyl.

The aluminum compound is chlorine-containing aluminum alkyl. Particularly preferred compounds are aluminum alkyl dichlorides and aluminum alkyl sesquichloride.

The titanium compound is a halogen-containing titanium compound, and a chlorine-containing titanium compound is preferable. A particularly preferred titanium compound is titanium tetrachloride.

The catalyst can be prepared by sequential contact with a carrier having the above-described compounds as described in EP-A-688794. Alternatively, it may be prepared by first preparing a solution with the components, and then contacting the carrier with the solution as described in WO-A-01155230. The catalyst is prepared according to the general manufacturing concept disclosed in European patent EP-A-688794 and in detail in the present application.

The above-mentioned catalyst is used together with a cocatalyst, also called an activator. Suitable cocatalysts are metal alkyl compounds, especially aluminum alkyl compounds. These compounds include alkyl aluminum halides such as ethylaluminium dichloride, diethylaluminium chloride, ethylaluminium sesquichloride, and dimethylaluminium chloride. The compounds may also be used in combination with trimethylaluminium, triethylaluminium, tri-isobutylaluminium, trihexylaluminium and tri-n-octylaluminium, Include the same trialkylaluminum compounds. Especially preferred cocatalysts are trialkylaluminum, triethylaluminum, trimethylaluminum, and tri-isobutylaluminum, and most preferably triethylaluminum (TEA).

The catalyst as described above is contacted with the cocatalyst as described above. The contacting of the catalyst and the cocatalyst may be carried out prior to introducing the catalyst into the polymerization reaction reactor or by separately introducing the two components into the polymerization reaction reactor (s).

For example, in a catalytic system according to the present invention, such as a combination of a catalyst and a cocatalyst according to the present invention, the molar ratio between aluminum in the cocatalyst and titanium in the catalyst is preferably from 20: 1 to 5: 1, Preferably from 15: 1 to 7: 1, and most preferably from 12: 1 to 8: 1.

Detailed Manufacturing Method

The first reactor is preferably a slurry phase reactor, most preferably a loop reactor, and the temperature is generally from 50 to 115 캜, preferably from 60 to 110 캜, especially from 70 to 100 캜. The pressure is generally from 1 to 150 bar, preferably from 1 to 100 bar.

In principle, the first reaction step can be carried out in any reactor. The first reactor is preferably a slurry reactor. The slurry phase polymerization can be carried out in a known reactor used for the slurry phase polymerization reaction. Such reactors include an ontinuous stirred tank reactor and a loop reactor. Particularly preferably, the polymerization reaction is carried out in a loop reactor. In such a reactor, the slurry circulates at a high rate along a closed pipe using a circulation pump. A loop reactor is disclosed, for example, in U.S. Patent Nos. 4,582,816, U.S. Pat. No. 3,405,109, U.S. Pat. No. 3,324,093, U.S. Patent Application Publication No. EP- 5,391, < RTI ID = 0.0 > 654. < / RTI >

Sometimes it is advantageous to perform a slurry phase polymerization reaction above the critical temperature and the intergranular pressure of the fluid mixture. Such an operation is described in US-A-5,391,654. The operating temperature is generally 85 DEG C or higher, preferably 90 DEG C or higher. Moreover, the temperature generally does not exceed 110 캜, and preferably does not exceed 105 캜. Under these conditions, the pressure is generally at least 40 bar, preferably at least 50 bar. Moreover, the pressure generally does not exceed 150 bar, and preferably does not exceed 100 bar. In a preferred embodiment, the slurry phase polymerization reaction step is carried out under supercritical conditions, wherein the reaction temperature and the reaction pressure correspond to a threshold value of the mixture formed by the hydrocarbon medium, the monomer, the hydrogen and optionally the comonomer, The temperature is lower than the melting temperature of the polymer produced.

The slurry may be discharged continuously or intermittently in a slurry bed reactor. A preferred method of intermittent discharge is to use a settling leg at the point where the slurry is concentrated before discharging a batch of slurry concentrated in the reactor. The use of the settling legs is described in particular in US-A-3,374,211, US-A-3,242,150, and EP-A-1 310 295. For continuous release, in particular, it is known from EP-A-891 990, EP-A-1 415 999, EP-A-1 591 460 and WO-A-2007/025640 Lt; / RTI > The continuous discharge advantageously combines the appropriate concentration method as disclosed in EP-A-1 415 999 and EP-A-1 591 460.

The settling leg is used to concentrate the slurry discharged from the reactor. Thus, the effluent stream contains, on average, more polymer than the slurry per volume in the reactor. This has the advantage of reducing the liquid that needs to be recycled to the reactor, and therefore the equipment cost is low. In a commercial scale plant, the fluid that is discharged with the polymer is evaporated in a flash tank which evaporates and is compressed by a compressor and recovered into the slurry bed reactor.

On the other hand, the settling leg releases the polymer hepatically. This allows the pressure and other variables within the reactor to vary with the period of the discharge. In addition, the discharge capacity depends on the size and number of settling legs and is limited. To overcome these disadvantages, continuous discharge is often preferred.

On the other hand, there is a problem that the continuous discharge generally requires discharging the polymer at the same concentration as that shown in the reactor. In order to reduce the content of compressed hydrocarbons, successive venting outlets are provided with suitable, for example, hydrocyclones or sieves, as described in EP-A-1 415 999 and EP-A-1 591 460, Which is advantageously combined with the concentrating device. The polymer-rich stream is then directed directly to the flash, and the polymer-lean stream is returned directly into the reactor.

In order to control the MFR ₂ of the polymerized polyethylene fraction in the slurry bed reactor, it is preferred that hydrogen is introduced into the reactor. The introduction of hydrogen is carried out so as to adjust the ratio of hydrogen to ethylene in the slurry bed reactor, preferably 300 to 750 mol / kmol, more preferably 400 to 600 mol / kmol.

The polyethylene fraction produced in the slurry phase reactor is an ethylene homopolymer fraction.

When the copolymer is polymerized, the comonomers are preferably selected from the group comprising 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene or mixtures thereof, -Butene and 1-hexene. In a preferred embodiment, the ethylene homopolymer is polymerized in the slurry phase reactor so that no comonomer is injected into the reaction step.

The residence time and the polymerization temperature in the slurry phase reactor are such that the ethylene homopolymer fraction relative to the total polyethylene base resin generally ranges from 44 to 54 wt%, preferably from 45 to 53 wt%, most preferably from 46 to 52 wt% .

The polymer fraction produced in the slurry bed reactor is preferably delivered to the gas phase reactor.

In the fluidized bed gas phase reactor, the olefin is polymerized in the presence of a polymerization catalyst in an upward gas flow. The reactor generally has a fluidized bed containing polymer particles that grow by containing an active catalyst provided on top of a fluidisation grid.

The polymer bed is a flow comprising a chain growth controller or chain transfer agent such as an olefin monomer and consequently a comonomer (s), consequently hydrogen, and, consequently, an inert gas It flows to help the gas. Here, the inert gas may be the same as or different from the inert gas used in the slurry bed reactor. The flowing gas is introduced into an inlet chamber provided at the bottom of the reactor. In order to ensure that the gas flow is distributed uniformly across the cross-sectional area of the inlet chamber, the inlet pipe is provided with a plurality of inlet channels, for example as disclosed in US-A-4,933,149 and European Patent EP-A-684 871, A flow dividing arrangement known in the art can be fitted.

The gas flow from the inlet chamber can pass through the fluidized bed through the fluidization grid toward the top. The fluidized grid is provided to divide the gas flow so as to uniformly pass the cross-sectional area of the fluidized bed. Sometimes, the fluidized-bed grid can be arranged to form a gas flow which is swept along the walls of the reactor, as disclosed in WO-A-2005/087261. Other types of fluidization grids are disclosed, among other things, in US-A-4,578,879, EP 600 414, and EP-A-721 798. Geldart and Bayens (The Design of Distributors for Gas-fluidised Beds, Powder Technology, Vol. 42, 1985).

The fluidizing gas flows through the fluidized bed. The superficial velocity of the fluidized gas must be higher than the minimum fluidization velocity of the particles contained in the fluidized bed, otherwise fluidization will not occur. On the other hand, the velocity of the gas must be lower than the pneumatic transport starting velocity, otherwise the entire fluidized bed will be accompanied by the fluidizing gas. The minimum fluidization rate and the pneumatic transport start velocity can be calculated according to known particle characteristics using conventional engineering methods. This is described by Geldart (Gas Fluidisation Technology, J. Wiley & Sons, 1996).

When the fluidizing gas is in contact with the fluidized bed containing the active catalyst, a gaseous reactant such as a monomer, and a chain transfer agent, the polymer product is produced by reacting in the presence of the catalyst. At the same time, the gas is heated by the reaction heat.

Unreacted fluidized gas is removed at the top of the reactor and then compressed and collected into the inlet chamber of the reactor. Before the flash reactants are introduced into the reactor, the flowable gas is introduced to compensate for losses resulting from reaction and product discharge. In general, analysis of the composition of the fluidized gas and introduction of gas components to keep the composition constant is generally known. The actual composition is determined by the catalyst used in the polymerization reaction and the required properties of the product.

The gas is then cooled in a heat exchanger to remove the heat of reaction. The gas is cooled to a temperature lower than the temperature of the fluidized bed to prevent the fluidized bed from being heated by the reaction. The gas can be cooled to a level where a portion of the gas condenses. When a droplet is introduced into the reaction zone, the droplet is evaporated. Thereafter, the heat of evaporation is used to remove the heat of reaction. This operation is referred to as a condensed mode and these variables are, among other things, described in WO-A-2007/025640, US-A-4,543,399, EP- And International Patent Publication No. WO-A-94/25495. Also, as disclosed in EP-A-696 293, a condensing agent can be added into the recycle gas stream. The condensing agent is at least partially condensed in the cooler with non-polymerizable components such as propane, n-pentane, isopentane, n-butane, or isobutane.

The polymeric product may be discharged continuously or intermittently from the gas phase reactor. These methods can also be used in combination. International Publication No. WO-A-00/29452 discloses a more continuous discharge. The hepatic release is, among other things, disclosed in US patent application Ser. No. 4,621,952, EP-A-188 125, EP-A-250 169 and EP-A- .

The upper portion of at least one gas phase reactor may comprise a portion called a disengagement zone. In this region the diameter of the reactor is increased to reduce the gas velocity and allow particles carried in the fluidized bed to be reintroduced into the fluidized bed with the fluidized gas.

The level of the fluidized bed may conform to other techniques known in the art. For example, the pressure difference between the bottom of the reactor and a particular height of the fluidized bed can be recorded throughout the length of the reactor, and the level of the fluidized bed can be calculated based on the pressure difference value. The values thus calculated are presented as time-averaged levels. An ultrasonic sensor or a radioactive sensor may also be used. These methods allow an immediate level to be obtained and averaged over time to obtain a time-averaged fluidized bed level.

If necessary, an antistatic agent may also be introduced into at least one gas phase reactor. Suitable antistatic agents and methods for using them are, among other things, those disclosed in US-A-5,026,795, US-A-4,803,251, US-A-4,532,311, US- Is disclosed in European patent EP-A-560 035. These are usually polar materials, among others, water, ketones, aldehyde alcohols.

The reactor may comprise a mechanical stirrer so that it can be further mixed in the fluidized bed. An example of the design of a suitable mechanical stirrer is described in European patent application EP-A-707 513.

The temperature of the gas phase polymerization reaction in the gas phase reactor is generally 70 ° C or higher, preferably 80 ° C or higher. The temperature is generally 105 占 폚 or lower, preferably 95 占 폚 or lower. The pressure is generally not less than 10 bar, preferably not less than 15 bar, in general not more than 30 bar, preferably not more than 25 bar.

Hydrogen is introduced into the reactor to adjust the melt flow rate of the polymerized polyethylene fraction in the first gas-phase reactor. The introduction of hydrogen is for adjusting the ratio of hydrogen to ethylene in the first gas-phase reactor, preferably 0.1 to 25 mol / kmol, more preferably 0.5 to 20 mol / kmol, most preferably 1.5 to 17 mol / kmol.

It is preferred that the ethylene copolymer fraction is produced in the gas phase reactor. Thus, the flowable gas stream comprises comonomers selected from the group consisting of alpha-olefin comonomers preferably having 3 to 12 carbon atoms, more preferably 4 to 8 carbon atoms. Suitable alpha-olefin comonomer species are 1-butene, 1-hexene, and 1-octene, with 1-butene and 1-hexene being most preferred. The comonomer used in the first gas phase reactor may be the same as or different from that used in the slurry phase reactor. The addition of the comonomer is to adjust the ratio of the comonomer to the ethylene, preferably 50 to 250 mol / kmol, more preferably 60 to 150 mol / kmol, and most preferably 70 to 100 mol / kmol.

In the gas phase reactor, the residence time and the polymerization temperature are such that the fraction of the ethylene copolymer to the total polyethylene resin is generally polymerized to 45 to 55 wt%, preferably 46 to 54 wt%, and most preferably 47 to 53 wt% Adjust.

Furthermore, it is preferable that the final polyethylene base resin discharged from the gas phase reactor contains fractions (A) and (B) together with a prepolymer selectively, and the density is more than 940.0 kg / m 3 and not more than 952.5 kg / desirable. The density of the base resin is preferably 941.0 kg / m3 or more and 952.0 kg / m3 or less, more preferably 942.0 kg / m3 or more and 951.0 kg / m3 or less.

The density of the polymeric resin constituted with the fraction (A) and optionally the prepolymer fraction is preferably higher than the density of the basic resin constituted with the fractions (A) and (B) and optionally with the prepolymer fraction.

The catalyst system may be introduced at any stage of the polymerization reaction, but is preferably introduced at the first polymerization stage. Most preferably, the catalyst system is only introduced into the first polymerization reaction step. The catalyst can be delivered to the polymerization reaction zone by methods known in the art. Thus, the catalyst is dispersed in the diluent and maintained as a uniform slurry. Particular preference is given to using oils with a viscosity of 20 to 1500 mPa * s as diluent as disclosed in WO-A-2006/063771. Further, the catalyst is mixed with the viscous mixture of the lubricant and the oil, and the resulting paste is injected into the polymerization reaction zone. In addition, the catalyst may be fixed according to the process disclosed in EP-A-428 054 and made into a catalyst mud, a portion of which may be introduced into the reaction zone.

In one embodiment of the present invention, the production method may further comprise a pre-polymerization step preceding the polymerization step. The purpose of the pre-polymerization reaction is to polymerize small amounts of polymer on the catalyst in low temperature and / or small concentration of monomers. By pre-polymerization the catalyst performance in the slurry can be improved and / or the properties of the final polymer can be modified. The pre-polymerization step is carried out in a slurry or gas phase. Preferably, the pre-polymerization is carried out in a slurry in which the loop reactor is preferential. Thus, the pre-polymerization step can be carried out in a loop reactor. The pre-polymerization is then preferably carried out in an inert diluent which is generally selected from the group consisting of methane, ethane, propane, n-butane, isobutene, pentane, hexane, heptane, ≪ / RTI > Preferably, the diluent is a mixture of low boiling hydrocarbons having 1 to 4 carbon atoms or hydrocarbons thereof. Most preferably, the diluent is propane.

The temperature in the pre-polymerization reaction step is generally 0 ° C to 90 ° C, preferably 20 ° C to 80 ° C, more preferably 55 ° C to 75 ° C.

The pressure is not a main factor, but is generally from 1 bar to 150 bar, preferably from 10 bar to 100 bar. The molecular weight of the prepolymer can be controlled by hydrogen as is known in the art. The antistatic agent can also be used to prevent the particles from adhering to each other or from adhering to the reactor walls, as disclosed in WO-A-96/19503 and WO-A-96/32420 have.

The catalysts are preferably all introduced into the pre-polymerization step. On the other hand, when the solid catalyst and the cocatalyst are separately introduced, if possible, only the co-catalyst part is introduced into the pre-polymerization step, and the remaining part is introduced into the subsequent polymerization step. Further, in such a case, it is necessary to inject as many cocatalysts into the pre-polymerization reaction step as necessary to obtain a sufficient polymerization reaction.

Embodiments preferably include the pre-polymerization step. Therefore, in a preferred embodiment of the present invention, the production method comprises a polymerization reaction step in a slurry-phase reactor and a pre-polymerization step following a polymerization reaction step in a gas phase reactor.

Preferably, the polyethylene composition of the present invention can be produced by a multi-step process that further includes a compounding step, which is generally carried out in the reactor in the extruder Followed by granulation into polymer pellets by methods known in the art for preparing the polyolefin compositions of the present invention.

Optionally, additives or other polymers, in particular, may be added to the composition in the amounts described above during the compounding step. Preferably, the compositions of the present invention made in the reactor are combined in the extruder with additives in a manner known in the art.

The extruder may be, for example, a commonly used extruder. An example of an extruder for the compounding step of the present invention is provided by a Japanese company such as SW 460P or JSW CIM90P (Japan Steel works, Kobe Steel or Farrel-Pomini) .

In one embodiment, the extrusion step is carried out at an input rate of 100 kg / h to 500 kg / h, more preferably 150 kg / h to 300 g / h. Preferably, the extruded amount as a commercial product is generally 10 to 50tons / h.

The screw speed of the extruder is preferably 250 rpm to 450 rpm, more preferably 300 rpm to 400 rpm.

In this extruding step, the specific energy input of the extruder is preferably 150 kWh / ton to 250 kWh / ton, more preferably 180 kWh / ton to 230 kWh / ton, and the SEI essentially ignores limited efficacy It is calculated directly from the power input of the extruder.

The melting temperature in the extrusion step is preferably 200 캜 to 300 캜, more preferably 230 캜 to 270 캜.

Preferably, the temperature in each zone of the extruder with four zones is set as follows: preferably zone 1 is set at 80 to 120 占 폚. Preferably, Region 2 is set at 180 to 220 占 폚. Preferably, region 3 is set to 230 to 270 占 폚. Preferably, region 4 is set to 160 to 200 占 폚.

More preferably, the four regions are set as follows: Region 1 is 90 to 110 캜, Region 2 is 190 to 210 캜, Region 3 is 240 to 260 캜, and Region 4 is 170 to 190 캜.

Pipe manufacturing

Polymer pipes are generally produced by extruders, or to a lesser extent by injection molding. Conventional plants for extrusion of polymeric pipes include extruders, die-heads, calibrators, cooling equipment, discharge devices, and devices for coiling and / or cutting the pipes.

The preparation of polyethylene materials for use as pressure pipes is described in Scheirs et al. (Scheirs, Bohm, Boot and Leevers: PE100 Resins for Pipe Applications, TRIP Vol. 4, No. 12 (1996) pp. 408-415 ). ≪ / RTI > The authors discuss the manufacturing techniques and properties of PE100 pipe materials. They pointed out that proper comonomer distribution and molecular weight distribution are important to optimize late crack growth and rapid crack propagation.

Pipe coating

A pipe, preferably a metal pipe, and most preferably an iron pipe, is usually coated with three layers according to the following procedure.

As is known in the art, it is desirable to properly prepare the surface of the pipe before coating. The surface of the pipe is usually checked for rust, dust, defects, discontinuities, and metal defects. All unnecessary material at the pipe surface is removed to properly adhere the coating to the pipe. Suitable cleaning methods include high pressure cleaning with air and water, grit or shot blasting, and mechanical blushing. Also, pickling and chromate pretreatment are sometimes used.

Generally, the pipe is heated by magnetic induction heating up to approximately 200 < 0 > C. The temperature is adjusted according to the material used for process speed and corrosion protection. When Epoxy Technos AR8434 is used in an iron pipe, it is preferably heated to 190 占 폚. The temperature is slightly reduced during the coating process.

Epoxy powder (at 23 ° C) is commonly used to spray using an epoxy gun, the pipe rotation speed is approximately 9 m / min. The thickness of the epoxy and other coating materials is set according to the particular requirements used last. For an epoxy layer (on land side) the normal thickness value is 70 to 200 microns, such as 135 microns.

As the corrosion inhibiting layer, for example, a material such as an epoxy resin and an organosilicon compound may be used. Examples of suitable epoxy resins are phenol-based epoxies and amino-based epoxies. These epoxy classes are sold under the trade names AR8434 (of Teknos), Scotchkote 226N (of 3M) and PE50-7191 of BASF (BASF) as follows. Suitable organosilicon compounds are disclosed in European published patent EP-A-1859926.

The extrusion of the contact layer and the top coating layer can be carried out, for example, using two single screw extruders. Their diameter is, for example, 30 to 100 mm, such as 60 mm, and the length is 15 to 50 L / D, such as 30 L / D. The temperature is generally controlled in various areas, and the temperature of the PE adhesive layer and the coating layer after die is 190 to 300 DEG C, such as 225 and 250 DEG C, respectively. The die width for the adhesive layer and the coating layer is 50 to 300 mm, such as 110 mm and 240 mm, respectively. Both the adhesive layer and the coating layer can be rolled so as to be in close contact with the silicon pressure roller. The thickness of the adhesive layer is generally 200 to 400 占 퐉, such as 290 占 퐉. The thickness of the coating layer is generally from 1 to 5 mm, preferably from 2 to 4 mm, such as 3.2 mm.

Materials suitable for use in the adhesive layer are olefin polymers grafted with an acid or acid anhydride such as polyethylene or polypropylene. Suitable polymers include, but are not limited to, fumaric acid modified polyethylene, fumaric acid anhydride modified polyethylene, maleic acid modified polyethylene, maleic acid anhydride modified polyethylene Fumaric acid-modified polypropylene, fumaric acid anhydride-modified polypropylene, maleic acid-modified polypropylene, and maleic acid anhydride-modified polypropylene. polypropylene). Examples particularly suitable for adhesive plastics are described in EP-A-1316598.

The upper coating layer preferably comprises the polyethylene composition according to the present invention.

The coated pipe is coated and then cooled, for example by supplying a water flow to the coated pipe surface.

Usage

Moreover, the present invention relates to an article, preferably a pipe, or a pipe fitting, or a pipe coated with a coating layer comprising an outer surface of a polyethylene composition as described above or a polyethylene composition prepared by the above-described process, wherein the polyethylene composition Relates to the use of an article, preferably a pipe, a pipe fitting, or a coated pipe.

Example :

1. Definitions

a) Melt flow rate

The melt flow rate (MFR) is measured in accordance with ISO 1133 and is expressed in g / 10 min. MFR is a measure of the fluidity of the polymer and is therefore processable. A higher melt flow rate means a lower viscosity of the polymer. The MFR ₅ of the polyethylene is measured at 190 ° C under a load of ₅ kg, the MFR ₂ of the polyethylene is measured at 190 ° C under a load of 2.16 kg, the MFR ₂₁ of the polyethylene is measured at 90 ° C . The FRR (flow rate ratio) value means the ratio of the flow velocity at different loads. Thus, FRR _21/5 is Means the value of MFR ₂₁ / MFR ₅ .

b) density

The density of the polymer was measured according to ISO 1183-1: 2004. Compressed test specimens prepared according to EN ISO 1872-2 (Feb 2007), expressed as kg / m3 by Method A.

c) Comonomer content

Quantitative nuclear magnetic resonance (NMR) spectroscopy was used to quantitate the comonomer content of the polymers.

The quantitative ¹³ C { ¹ H} NMR spectrum was recorded using a Bruker Advance III 500 NMR spectroscope operating at 500.13 and 125.76 MHz for ¹ H and ¹³ C, respectively, in the molten state. All spectra were measured using a magic-angle spinning (MAS) probe head optimized for all pneumatic nitrogen gases at 7O 0 C at 150 ° C. Approximately 200 mg of material was packed in a 7 mm outer diameter zirconia MAS rotor and spun at 4 kHz. These settings were chosen primarily for high sensitivity requiring rapid identification and accurate quantification. The standard single-pulse excitation uses a short recirculation delay of 3s {1, 3} and the RS-HEPT decalculating system {[1], [2], [ 4], [5]}. A total of 1024 (1k) transitions were required per spectrum. This setting was chosen to have high sensitivity for low comonomer content.

The quantitative ¹³ C { ¹ H} NMR spectra were developed and integrated, and the quantitative properties were measured by a custom spectroscopy automated program. All chemical shifts refer internally to the bulk methylene signal (δ +) at 30.00 ppm [9].

Characteristic signals corresponding to the incorporation of 1-hexene were observed and all the contents for all other monomers appearing in the polymer were calculated.

H = I _{* B4}

For example, in the absence of other signals representing other comonomer sequences, such as incorporation of a continuous comonomer, the total amount of 1-hexene comonomer observed was calculated solely based on the content of the isolated 1-hexene sequence.

H _total = H

Characteristic signals resulting from the saturated terminal group were observed. The content of the saturated end groups was quantified using the average of the integration of the signals at 22.84 and 32.23 ppm assigned to the 2s and 2s sites, respectively.

S = (1/2) * ( _I2S + _I3S )

The relative content of ethylene was quantified using the integration of the bulk methylene (δ +) signal at 30.00 ppm.

E = (1/2) * I _{? +}

The total ethylene comonomer content was calculated taking into account the ethylene units that are based on the bulk methylene signal and are present in the observed comonomer sequences or end groups.

E _total = E + (5/2) * B + (3/2) * S

The total mole fraction of 1-hexene in the polymer was calculated as follows.

fH = (H _total / (E _total + H _total )

The total amount of 1-hexene incorporated comonomer in mole percent was calculated in molar ratios in the usual way.

H [mol%] = 100 * fH

The total amount of comonomer (s) of 1-hexene in weight percent was calculated in molar ratios in a standard manner.

H [wt%] = 100 * (fH * 84.16) / ((fH * 84.16) +

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[2] Parkinson, M., Klimke, K., Spiess, H. W., Wilhelm, M., Macromol. Chem. Phys. 2007; 208: 2128.

[3] Pollard, M., Klimke, K., Graf, R., Spiess, H. W., Wilhelm, M., Sperber, O., Piel, C., Kaminsky, W., Macromolecules 2004; 37: 813.

[4] Filip, X., Tripon, C., Filip, C., J. Mag. Resn. 2005, 176, 239

[5] Griffin, J. M., Tripon, C., Samoson, A., Filip, C., and Brown, S. P., Mag. Res. in Chem. 2007 45, S1, S198

[6] Castignolles, P., Graf, R., Parkinson, M., Wilhelm, M., Gaborieau, M., Polymer 50 (2009) 2373

[7] Zhou, Z., Kuemmerle, R., Qiu, X., Redwine, D., Cong, R., Taha, A., Baugh, D. Winniford, B., J. Mag. Reson. 187 (2007) 225

[8] Busico, V., Carbonniere, P., Cipullo, R., Pellecchia, R., Severn, J., Talarico, G., Macromol. Rapid Commun. 2007, 28, 1128

[9] J. Randall, Macromol. Sci., Rev. Macromol. Chem. Phys. 1989, C29, 201.

d) Rheological parameter

The characteristics of the polymer melt by dynamic shear measurement are in accordance with ISO standards 6721-1 and 6721-10. The measurements were carried out in a 25 mm parallel plate array and by Anton Paar MCR501 stress controlled rotational flow meter (Anton Paar MCR501 stress controlled rotational rheometer). Measurements are carried out on a compacted plate, using a nitrogen environment and setting the strain rate in a linear viscoelastic system. The vibration shear test was carried out at 190 DEG C with a frequency in the range of 0.01 to 600 rad / s and a frequency of 1.3 mm.

Dynamic shear tests allow the shear strain or shear stress (the strain and stress, respectively, to be controlled modes) to vary evenly with the sinusoidal variation of the probe. In a controlled strain experiment, the probe is a sinusoidal strain expressed as:

? (t) =? ₀ sin (? t) (1)

If a strain is applied in the linear viscoelastic system, the result is sinusoidal stress as described below.

σ (t) = σ ₀ sin (ωt + δ) (2)

Where σ ₀ and γ ₀ are the stress and strain amplitudes, ω is the angular frequency, δ is the phase shift (loss angle between applied strain and stress response), and t is time.

Dynamic test results are generally expressed as averages of various other rheological functions and are defined as the shear storage modulus G ', the shear loss modulus G ", the composite shear modulus G *, the composite shear viscosity η *, the dynamic shear viscosity η' Quot ;, and the loss tangent tan < RTI ID = 0.0 > eta, < / RTI >

cosδ [Pa] (3)G '=

cos? [Pa] (3)

sinδ [Pa] (4)G "=

sin? [Pa] (4)

G * = G '+ iG "[Pa] (5)

? * =? ' - i? "[Pa · s] (6)

[Pa·s] (7)η '=

[Pa · s] (7)

[Pa·s] (8)η '' =

[Pa · s] (8)

The determination of the so-called shear fluidity index is related to the MWD dependent on Mw, as set forth in Equation 9 below.

(9)

(9)

For example, SHI _{(2.7 / 210)} is expressed as Pa · s and is defined as a composite viscosity value. The G * value corresponding to 2.7 kPa is measured, and the G * value corresponding to 210 kPa is measured. Value.

Values of storage elastic modulus (G '), loss elastic modulus (G "), composite elastic modulus (G *) and complex viscosity (η *) were obtained as a function of frequency (ω).

Thus, for example, _{η * 300rad / s (eta *} 300rad / s) is 300 rad / s is used as abbreviation for the complex viscosity at a frequency _{of, η * 0.05rad / s (eta} * 0.05rad / s) are 0.05rad / s is used as the abbreviation for the complex viscosity.

The loss tangent tan (delta) is the loss modulus (G ") and is defined as the ratio of the storage modulus (G '). Thus, for example, tan _{0 .05} is at a given frequency, Short of the ratio of the loss modulus (G ") and storage modulus (G ') of from 0.05rad / s and, ₃₀₀ is tan Is the abbreviation of the ratio of the loss elastic modulus (G ") to the storage elastic modulus (G ') at 300 rad / s.

The elastic equilibrium tan _{0 .05} / tan ₃₀₀ is defined as the ratio of loss tangent tan _{0 .05 to} tan ₃₀₀ .

In addition, the rheological function described above may also determine other rheological parameters such as so-called elasticity index EI (x). The elasticity index Ei (x) can be described as a storage elasticity value G 'for the loss elastic modulus value G "of x kPa as shown in Equation (10).

[Pa] (10)

[Pa] (10)

For example, EI (5 kPa) is determined by the storage modulus value G 'determined for G "corresponding to 5 kPa.

The viscosity eta ₇₄₇ is measured at a very low, constant shear stress of ₇₄₇ Pa, e.g., the larger eta ₇₄₇ is inversely proportional to the gravity flow of the polyethylene composition, such as low sagging of the polyethylene composition.

The polydispersity index PI is defined by Eq. 11.

, ω_COP = ωfor (G'= G") (11) PI =

,? _COP =? for (G '= G ") (11)

Here, ω _COP is Over angular displacement measured by the angular frequency with respect to the storage elastic modulus G 'corresponding to the loss elastic modulus G ".

The values determined by the single point interpolation procedure are defined by the Rheoplus software. The situation for a given G * value is not obtained by experiment and is the value determined by extrapolation using the same procedure as before. In both cases (interpolation or extrapolation), the "interpolate y-values to x-values from parameter" and "logarithmic interpolation type" And the selection in

references :

[1] Rheological characterization of polyethylene fractions "Heino, EL, Lehtinen, A., Tanner J., Seppaelae, J., Neste Oy, Porvoo, Finland, Theor. Appl. Rheol., Proc. Int. (1992), 1, 360-362

[2] The influence of molecular structure on some rheological properties of polyethylene ", Heino, E. L., Borealis Polymers Oy, Porvoo, Finland, Annual Transactions of the Nordic Rheology Society, 1995.).

[3] Definition of terms relating to non-ultimate mechanical properties of polymers, Pure & Appl. Chem., Vol. 70, No. 3, pp. 701-754,1998.

e) Molecular Weight

The polydispersity index (PDI = Mw / Mn, where Mn is the number average molecular weight and MW is the weight average molecular weight (Mw) and the weight average molecular weight (Mw) Average molecular weight) was determined by gel permeation chromatography (GC) according to ISO 16014-4: 2003 and ASTM D 6474-99e using the following formula:

(1)

(One)

(2)

(2)

(3)

(3)

For a given elution volume spacing DELTA V _i , where A _i and M _i are the chromatographic peak silica region and the polyolefin molecular weight (MW).

PolymerChar's GPC apparatus is equipped with an infrared (IR) detector using 3x Olexis and 1x Olexis Guard column from Polymer Laboratories and 160 2, 4-trichlorobenzene (TCB, 2,6-di tert butyl-4-methyl-phenol) 250 mg / L) and 200 [mu] l of the sample solution were injected at a constant rate of 1 mL / min. The set of columns was calibrated using Universal Calibration according to ISO 16014-2: 2003 by a polystyrene (PS) standard with a narrow MWS of at least 15 at 0.5 kg / mol to 11500 kg / mol. For the PS, PE, and PP used, the Mark Houwink constant is used as described for ASTM D 6474-99. All samples were loaded with 8 mL (equivalent to the mobile phase) of stabilized TCB (identical to the mobile phase) under conditions of continuous mild mixing in an autosampler of a GPC apparatus for 2.5 hours for PP at 3O < 0 & 160 < 0 > C).

f) Charpy Notch Impact Strength

Charpy impact strength was measured according to ISO 179 / 1eA: 2000 on a V * -notch sample of 80 * 10 * 4 에서 at 0 캜 (Charpy impact strength (0 캜)). The samples were prepared by cutting a 4 mm thick plate prepared by compression molding according to ISO 293: 2004 using the conditions defined in chapter 3.3 of ISO 1872-2: 2007.

g) Tensile modulus (23 ° C)

According to the stiffness measurement, the tensile modulus (E-modulus) of the composition was measured at 23 DEG C for a compression molded sample according to ISO 527-2: 1993. The sample (Type 1B) was prepared by cutting a 4 mm thick plate prepared by compression molding according to ISO 293: 2004 using the conditions defined in chapter 3.3 of ISO 1872-2: 2007. The elastic modulus was measured at a rate of 1 mm / min.

f) Tensile Properties (-45 ℃)

The tensile strength, which consists of the tensile strength at the yield point, the strain at the yield point and the elongation at break (e.g., the tensile strain at break) is measured according to ISO 527-1 (crosshead speed 50 mm / min) at a temperature of -45 캜.

i) Mg, Al, and Ti content / ICP analysis

The catalyst, in particular the analysis, was carried out by taking a solid sample of mass M. Samples were diluted to the known volume V by dissolving in nitric acid (HNO ₃ , 65% for volume V, 5%) and fresh deionized water (DI) (5% for volume V). The solvent was further treated with hydrofluoric acid (HF, 40% for volume V, 3%) and diluted to deionized water to a final volume of V and allowed to settle for 2 hours.

The analysis was performed using a thermally configurable iCAP 603 (Thermo Elemental iCAP 6300) Inductively Coupled Plasma-Optical Emission Spectrometer (ICP-OES) calibrated by blank (5% HNO ₃ , and 3% HF solution) And at a standard temperature of 0.5 ppm, 1 ppm, 10 ppm, 50 ppm, 100 ppm, and 300 ppm in Al, Mg, and Ti in a solution of 5% HNO ₃ and 3% HF.

Just prior to analysis, the calibration was 'resloped' using the blank and 100 ppm standard, and a quality control sample (QC sample, solution of 5% HNO ₃ , 3% HF in deionized water 20 ppm Al, Mg, and Ti) is performed to confirm the slope correction. Further, the QC sample is performed after the end of the planned analysis set and every fifth sample.

The Mg content was 285.213 nm and the Ti content was recorded using a 336.121 nm line. The content of aluminum was recorded through a line of 167.079 nm and the Al concentration in the ICO sample was recorded at 167.079 nm when the Al concentration was 0 to 10 mmp (corrected to 100 ppm only), and the Al concentration was recorded at 396.152 nm at the Al concentration exceeding 10 ppm .

The reported values are an average of three consecutive aliquots obtained from the same sample and are related to the initial mass and dilution volume of the sample being entered into the software and returned to the original catalyst.

j) The particle size of the catalyst

The particle size is measured with a Coulter Counter LS 200 using n-heptane at ambient temperature.

2. Example

Catalyst preparation

Composite Manufacturing:

87 kg of toluene was added to the reactor. 45.5 kg of Bomag A (butyloctylmagnesium) in heptane was then added to the reactor. 161 kg of 99.8% 2-ethyl-1-hexanol were then introduced into the reactor at a flow rate of 24 to 40 kg / h. The molar ratio between bomag A and 2-ethyl-1-hexanol was 1: 1.83.

Preparation of solid catalyst component:

330 kg of silica (fired silica, Sylopol ^® 2100) and pentane (0.12 kg / kg carrier) were charged into the catalyst preparation reactor. Ethylaluminium dichloride (EADC) (2.66 mol / kg silica) was then added into the reactor for 2 hours at a temperature below 40 ° C and mixed for 1 hour. The temperature during mixing was 45 to 50 占 폚. Then, the Mg composite (2.56 mol Mg / kg silica) prepared as described above was added at 50 DEG C for 2 hours and continuously mixed at a temperature of 45 to 50 DEG C for 1 hour. Pentane 0.84 kg pentane / kg silica was added to the reactor and the slurry was stirred at a temperature of 45-50 C for 4 hours. Finally, TiCl ₄ (1.47 mol / kg silica) was added to the reactor at a temperature of 55 ° C for a minimum of 1 hour. The slurry was stirred for 5 hours at a temperature of 450-60 < 0 > C. The catalyst was then dried by nitrogen purge.

Molar composition of prepared catalyst:

AI / Mg / Ti = 1.5 / 1.4 / 0.8 (mol / kg silica).

The Example  Multistage Polymerization Method for IE1

A loop reactor with a volume of 50 dm 3 was operated at 70 ° C at a pressure of 62 bar. To prepare the prepolymer fraction, 5.0 g / h of a gas mixture containing 36.4 kg / h of propane diluent, 0.8 kg / h of ethylene and 25% of hydrogen was charged into the reactor. In addition, the polymerization reaction catalyst prepared according to the above description was introduced into the reactor at a rate of 9.9 g / h. Triethylaluminium (TEA) cocatalyst was added at 5.7 g / h. No additional comonomer was added into the reactor. The polymerization reaction rate was 0.7 kg / h, and the conditions in the reactor were as shown in Table 1.

The polymer slurry discharged from the loop reactor was charged to a volume of 500 dm < ³ > Lt; / RTI > reactor. This second loop reactor was operated at 95 < 0 > C at a pressure of 57 ar. 134 g / h of a gas mixture containing 96 kg / h of propane diluent, 34 kg / h of ethylene and 25% by volume of hydrogen was charged into the reactor. A triethylene aluminum (TEA) cocatalyst was added at 5.7 g / h. No additional comonomer or catalyst was added into the reactor. The polymerization reaction rate was 30.8 kg / h, and the conditions in the reactor were as shown in Table 1.

The polymer slurry discharged from the second loop reactor was transferred into a flash vessel operating at a temperature of 70 [deg.] C and a pressure of 3 bar at which substantially hydrocarbons were removed from the polymer. The polymer was then introduced into a gas phase reactor operating at a temperature of 85 ° C and a pressure of 20 bar. In addition, 42 kg / h of ethylene, 1.5 kg / h of 1-butene and 3.4 g / h of hydrogen were fed into the reactor. The polymerization reaction rate was 28 kg / h. The reaction conditions are shown in Table 1.

The resulting polymer was purged with nitrogen (approximately 50 kg / h) for 1 hour, stabilized with 2200 ppm Irganox B225 and 1500 ppm calcium stearate (Ca 2 stearate), followed by counter-rotating twin screw extruder) CIM90P (manufactured by Japan Steel Works) with 3.0 wt% of carbon black and pellets at a throughput of 221 kg / h and a screw speed of 349 rpm.

The Example  Multistage Polymerization Method for IE2 to IE3

IE2 to IE3, which are novel examples, were polymerized using the same reactor arrangement and the same catalyst and cocatalyst in the novel example IE1. The polymerization conditions and the introduction into other reactors and the compounding conditions are as shown in Table 1. < tb > < TABLE >

Comparative Example  Multistage polymerization method for CE1 to CE5

The polymerization reaction was carried out by repeating the catalyst Lynx 200 of BASF Co. in a usual manner. TEA was again used as the co-catalyst. As can be seen from the data in Table 1, the catalysts led to a balance of significant differences in properties.

IE1 IE2 IE3 CE1 CE2 CE3 CE4 CE5 Prepolymerizing agent : On On On On On On On On Temperature [° C] 70 70 70 60 60 60 60 60 Pressure [bar] 62 62 62 62 61 60 60 60 Catalyst input [g / h] 9.9 10.0 10.2 2.4 3.8 4.2 4.8 4.3 Catalyst feed [g / h] 5.7 5.7 5.2 3.4 4.5 4.5 5.5 4.7 C ₂ input [kg / h] 0.8 0.7 0.7 2.0 2.0 2.0 2.0 2.0 H ₂ input [g / h] 5.0 5.0 5.0 10.4 10.4 9.9 10.0 10.7 C ₃ input [kg / h] 36.4 36.4 36.4 47.2 47.0 46.9 46.9 46.6 Manufacturing speed [kg / h] 0.7 0.7 0.6 1.9 1.9 1.9 1.9 1.9 Split [wt%] 1.2 1.1 1.0 2.8 2.3 2.6 2.8 2.5 Loop: Temperature [° C] 95 95 95 95 95 95 95 95 Pressure [bar] 57 57 57 58 56 57 57 57 Catalyst feed [g / h] 5.7 5.7 5.2 2.4 4.5 4.5 5.1 4.6 Al / Ti [mol / mol] 15 13 13 C ₂ input [kg / h] 34 34 34 37 37 36 38 38 H ₂ input [kg / h] 134 162 188 37.4 54.6 96.2 181 90.6 C ₃ input [kg / h] 96 96 95 96.5 91.1 90.7 90.7 88.5 H ₂ / C ₂ [mol / kmol] 466 489 558 235 260 421 765 440 C ₂ - concentration [mol%] 4.9 5.7 6.0 2.3 3.5 3.6 3.9 3.3 Split [wt%] 52 52 46 52 43 46 52 47 MFR ₂ [g / 10 min] 298 200 283 45 45 207 723 171 weather: Temperature [° C] 85 85 85 85 85 85 85 85 Pressure [bar] 20 20 20 20 20 20 20 20 C ₂ input [kg / h] 42 42 50 33 62 52 41 48 H ₂ input [kg / h] 3.4 3.8 13 10 56 25 12 22 C ₄ Loading [kg / h] 1.5 1.6 2.3 1.2 3.0 2.0 2.9 2.6 H ₂ / C ₂ ratio [mol / kmol] 7.8 7.7 15 24 54 33 23 25 C ₄ / C ₂ [mol / kmol] 74 74 81 58 83 70 131 85 C ₄ / C ₂ Feed rate [g / kgPE] 36 39 45 37 48 39 71 54 C ₂ - concentration [mol%] 11.9 12.1 15.6 6.6 21.4 16.5 8.8 11.1 Split [wt%] 47 47 53 45 55 51 45 50 Density [kg / m3] 950.3 950.1 947.7 949.1 945.6 947.0 946.5 948.2 C ₄ content [mol%] 0.37 0.39 0.45 0.47 0.61 0.55 0.88 0.60 Compounding : Input [kg / h] 221 221 221 283 263 255 230 231 Screw speed [rpm] 349 349 349 401 385 400 453 450 SEI [kWh / t] 201 204 212 230 229 228 228 237 Melting temperature [캜] 237 247 241 267 260 258 257 263 Zone 1 Temperature [캜] 100 100 100 100 100 100 100 100 Zone 2 Temperature [캜] 200 200 200 200 200 200 200 200 Zone 3 Temperature [캜] 250 250 250 250 250 250 250 250 Zone 4 Temperature [캜] 180 180 180 180 180 180 180 180 Carbon black [wt%] 3.0 1.9 2.5 2.4 2.4 2.2 2.5 2.4 Density [kg / m3] 965.0 958.9 960.9 960.6 957.5 959.8 958.9 957.6 MFR ₅ [g / 10 min] 0.23 0.21 0.24 0.46 0.67 0.32 0.65 0.37 MFR ₂₁ [g / 10 min] 6.8 5.8 5.5 13.0 12.0 8.1 21.0 11.0 FRR _21/5 29.6 27.6 22.9 28.2 17.9 25.3 32.3 29.7 Mw [10 ³ g / mol] 219 223 209 200 163 203 180 195 Mn [10 ³ g / mol] 10.0 11.0 12.0 10.5 12.4 9.7 6.8 8.6 Mz [10 ³ g / mol] 1127 1159 982 1185 713 1075 1090 1090 Mw / Mn 21.6 20.7 18.1 19.1 13.2 20.8 26.6 22.6 PI [Pa ^-1 ] 2.3 2.4 1.8 3.6 1.6 2.4 3.3 3.0 Complex viscosity at 0.05 rad / s eta [kPa s] 1.508E + 05 1.647E + 05 1.354E + 05 1.055E + 05 0.586E + 05 1.126E + 05 0.790E + 05 1.089E + 05 Complex viscosity at 300 rad / s eta [kPa s] 1294 1329 1469 1005 1178 1180 851 1027 Eta ₇₄₇ [Pas] 3.99 E + 05 4.88 E + 05 3.20 E + 05 4.10 E + 05 1.16 E + 05 3.49 E + 05 2.12 E + 05 3.39 E + 05 G '(5 kPa) [Pa] 2403 2496 2182 3079 2173 2663 2763 2792 G '(2 kPa) [Pa] 811 843 729 1056 706 917 904 947 SHI _{2 .7 / 210} 35.3 37.5 22.8 66.6 19.7 39.0 66.3 56.1 SHI _1/100 14.4 15.6 10.5 28.6 9.7 17.1 22.5 21.7 Tensile modulus, 23 캜 [MPa] 1123 1035 1107 1102 1025 1063 1045 1089 Tensile stress at yield point, -45 ° C [MPa] 49.4 49.3 47.3 48.5 46.0 47.4 48.5 48.8 Tensile strain at tensile stress, -45 ℃ [%] 6.0 6.0 6.3 6.1 6.5 6.1 5.6 5.8 Tensile strength, -45 ° C [MPa] 49.4 49.3 47.3 48.5 46.0 47.4 48.5 48.8 Tensile strain at tensile strength, -45 ° C [%] 6.0 6.0 6.3 6.1 6.5 6.1 5.6 5.8 Breaking tensile stress, -45 ° C [MPa] 20.0 24.5 27.6 17.1 19.4 18.9 22.5 18.2 Elongation at break, -45 ° C [%] 81 109 149 33 79 85 147 64 Elongation at break (-45 ° C) / comonomer content [% / mol%] 218 279 331 68 130 155 167 107 Charpy NIS, 0 캜 [kg / m 3] 20.4 22.0 23.7 14.2 16.8 17.2 12.2 14.5

(Table 1 shows polymerization reaction conditions.)

Claims (14)

A polyethylene composition comprising an ethylene copolymer having at least one alpha olefin comonomer having from 3 to 12 carbon atoms and having a density of at least 940.0 kg / m 3 and at most 952.5 kg / m 3, as measured according to ISO 1183-1: 2004 as,
The composition has a melt flow rate MFR ₅ (190 캜, 5 kg) of 0.10 to 3.0 g / 10 min measured according to ISO 1133, a storage elastic modulus G '(2 kPa) of 600 Pa to 900 Pa, a shear thinning index SHI _{2 .7 / 210} is 20 to 50,
Said composition having an elongation at break (EB) at -45 캜, depending on the molar content (mol. CC) of the comonomer of the base resin according to the following formula:
EB [%] ≥ 175 [% / mol%] · mol. CC [mol%]
Wherein said elongation at break is measured according to ISO 527-1 at a temperature of -45 DEG C and the molar content (mol. CC) of said comonomer is greater than the molar content of said alpha-olefin units in the total content of monolithic units of said base resin. Lt; RTI ID = 0.0 > olefin < / RTI > comonomer. The method according to claim 1,
Polydispersity index (PI) is 1.5Pa and 3.0Pa ^{-1 -1} over a range, the polyethylene composition described below. 3. The method according to claim 1 or 2,
Wherein the base resin contains 0.1 to 3.0 mol% of units derived from at least one of the alpha olefin comonomers having 3 to 12 carbon atoms. The method according to any one of the preceding claims,
Wherein the tensile modulus at 23 占 폚 is 900 MPa or more. The method according to any one of the preceding claims,
And a Charpy notched impact strength at 0 캜 of 10 kJ / m 3 or more. The method according to any one of the preceding claims,
MFR ₂₁ For the flow rate ratio of the ratio of _{MFR 5 (flow rate ratio) FRR} 21/5 of 15 to 40 is, the polyethylene composition. The method according to any one of the preceding claims,
Wherein the complex viscosity at 0.05 rad / s eta * _{0.05 rad / s} is 100000 Pas to 220,000 Pas. The method according to any one of the preceding claims,
Wherein the molecular weight distribution, which is a ratio of Mw / Mn, is 10 to 30. The method according to any one of the preceding claims,
Wherein the base resin comprises at least two ethylene homopolymers or ethylene copolymer fractions (A) and (B) having different weight average molecular weights (Mw)
Wherein said fraction (A) is an ethylene homopolymer and said fraction (B) is a copolymer of ethylene and at least one alpha-olefin comonomer unit having from 3 to 12 carbon atoms,
Herein, the fraction (A) has a melt flow rate MFR ₂ (190 °, 2.16 kg) of 100 to 400 g / 10 min,
The fraction (A) is present in an amount of 44 to 54 wt.% Based on the base resin. 1. A polyethylene composition produced by a multistage process, the multistage process comprising:
a) polymerizing ethylene under a catalyst in the first reactor as an intermediate step of preparing a melt flow rate MFR ₂ (190 °, 2.16kg) is from 100 to 400 g / 10min,
Wherein the catalyst is a silica supported Ziegler-Natta catalyst having a molar composition comprising:
Al: 1.30 to 1.65 mol / kg silica,
Mg: 1.25 to 1.61 mol / kg silica,
Ti: 0.70 to 0.90 mol / kg silica,
Having a mean particle size (D50) of 7 to 15 占 퐉, preferably 8 to 12 占 퐉;
b) transferring the reaction product to a gas phase reactor,
(i) supplying ethylene and a comonomer to the gas phase reactor,
(ii) further polymerizing the intermediate,
Producing a base resin having a density of not less than 940.0 kg / m 3 and not more than 952.5 kg / m 3, measured according to ISO 1183-1: 2004; And
c) extruding the base resin into a polyethylene composition,
Wherein the polyethylene composition has a melt flow rate measured according to _{ISO 1133 MFR 5 (190 ℃,} 5kg) is 0.10 to 3.0g / 10min, and the storage elastic modulus G '(2kPa) The 600Pa to 900Pa, the shear thinning index SHI _{2 .7 / 210} is from 20 to 50 and has a breaking elongation (EB) at -45 캜 dependent on the molar content (mol. CC) of the comonomer of the base resin according to the following formula:
EB [%] ≥ 175 [% / mol%] · mol. CC [mol%]
Wherein said elongation at break is measured according to ISO 527-1 at a temperature of -45 DEG C and the molar content (mol. CC) of said comonomer is greater than the molar content of said alpha-olefin units in the total content of monolithic units of said base resin. Lt; RTI ID = 0.0 > olefin < / RTI > comonomer. An article comprising the polyethylene composition according to any one of claims 1 to 10. 12. The method of claim 11,
Wherein said article is a pipe or pipe fitting. 12. The method of claim 11,
Wherein the article is a pipe, the outer surface of which is coated with a coating layer comprising a polyethylene composition according to any one of claims 1 to 10. 10. Use of the polyethylene composition according to any one of claims 1 to 10 for the manufacture of an article.